The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Injections in different portions of a combustion cycle have different effects upon the resulting combustion cycle, including effects upon work output of the engine, emissions, and combustion stability. Fuel injection timing in each of multiple fuel injections may be controlled, adjusted, or corrected, for example, by monitoring an engine load and utilizing calibrated values to determine an appropriate timing of each pulse for a multiple injection scheme. However, such methods are only as accurate as the calibration values allow. Further, it will be appreciated that such methods are reactive and include a time lag, controlling engine operation some period after the measurement of the inputs. It will additionally be appreciated that engine output is a term described for an entire engine, and generally cannot provide particular information about the combustion occurring in a particular cylinder.
A variety of intrusive and non-intrusive pressure sensing means are known for sensing pressure within an internal combustion engine cylinder when the engine is motoring and when the engine is firing. In-cylinder pressure measurements can be utilized to estimate different aspects of a combustion cycle. Such pressure measurements can be measured and processed in real time during the operation of the engine. Additionally, such pressure measurements can be tracked on a cylinder-by-cylinder basis.